The Layers to Bottom command lowers the selected
layers to the bottom of the layer stack. If the selected layers already end
at the bottom of the stack, or if there is only one layer, this menu entry
is disabled.
7.22.1. コマンドの呼び出し方
You can access this command
From the main menu through
Layer → Stack → Layers to Bottom.
By pressing the Shift key and clicking on the
down-arrow icon at the bottom of the Layers dialog.
